JPS587149A - Photoconductive receptor - Google Patents

Abstract

PURPOSE:To obtain a photoconductive receptor provided with a photo sensitive layer having photosensitive characteristics over a wide wavelength range covering the whole visible light range and most of the wavelenght range of sunbeams. CONSTITUTION:The photosensitive layer of this receptor is formed with a blue sensitive part made of amorphous silicon hydride contg. 6-37atomic% nitrogen and a red sensitive part made of silicon composed of uniformly distributed microcrystalline silicon and amorphous silicon which have a continuously changing crystal structure. By adding such a larg quantity of nitrogen atoms to amorphous silicon hydride, the blue sensitivity can be enhanced. The constituent silicon of the red sensitive part is extremely superior to amorphous silicon in red sensitivity.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a conductive photoreceptor having a photosensitive layer having a conductive effect on a substrate.

To receive the light irradiation purple, ridenryo-IF hole vs. ligature,
This electron-iF. The electrically conductive effect 11 (which has a low resistivity due to the cap current flowing through the hole pair) and the conductive photoreceptor with the photosensitive layer gold substrate is used as a photodetecting means and a photoelectric conversion means. Currently, it is widely used as a detector, for example, as the original detection part of an image sensor, a photoelectric conversion cell of a solar cell,
r Photographic photoreceptor, etc. ('C).

In recent years, amorphous silicon has been used to form the sensitive layer, as it has a simple manufacturing process, a large extinction coefficient, can be easily made into a large area, and is capable of controlling Ic p-n type. Due to this, special attention has been paid to V'C.

However, amorphous silicon has a narrow spectral sensitivity region;
In particular, it has a serious drawback that it cannot adequately cover the entire visible region and the wavelength region of sunlight, and therefore it has a number of drawbacks similar to those when amorphous silicon is used as a photosensitive layer in actual devices. become. In the case of an image sensor, it is impossible to capture an image by covering the entire visible Y color range.
In the case of a solar cell, sufficient conversion efficiency cannot be obtained, and in the case of an electrophotographic photoreceptor, only a specific color can be copied.

Therefore, various devices with photoconductive photoreceptors used as amorphous/licon photosensitive layers have not yet been generally accepted as fully satisfactory in terms of optical properties. 4. There is something to do.

This purpose is to create a blue-sensitive light-receiving area made of hydrogenated amorphous silicon containing 6 to 37 atoms of nitrogen, and a uniform distribution of microcrystalline silicon and amorphous silicon. High-quality silicon is a photosensitive layer composed of a red sensitive tail made of silicon whose crystal structure is continuous (and has a structure that changes).
will be collected.

The present inventors have discovered by conducting the experiments described below that the blue sensitivity can be improved by including a total amount of nitrogen atoms in hydrogenated amorphous silicon.

The specimen used in the experiment was prepared as follows.

Quartz substrate or S+ installed in glow discharge reaction chamber
A vertical magnetic field of VC0.8K and G is applied to the substrate, and then I
-12 meeting lO mouth] Chemical paper containing M-13 gas in the range of 6 to 95 mo1% with respect to 5il-T4 gas containing O1%? While being introduced into the reaction chamber at a constant flow rate, glow discharge was performed under the discharge conditions of a frequency of 13.56 MHz and 1 power of 20 W, thereby completely fabricating hydrogenated amorphous silicon containing nitrogen on the substrate. The substrate temperature is 25
A temperature of 0-300°C was used, typically 300'C.

Next, the optical and electrical properties of the nitrogen-containing hydrogenated amorphous silicon obtained as described above are shown. 1-0 FIG. 1 shows the photon energy dependence of the extinction coefficient. 5il (NH3 gas 226 for 4 gases
Mo1% content L y N#+ +Sil I 40I (2
It can be seen that the amorphous silicon deposited by gas is on the high energy side when compared with amorphous silicon which does not contain any nitrogen. Figure 2 shows the relationship between the extinction coefficient and the photon energy.
This figure shows the dependence of the optical gap on the mol concentration of N[]3 gas on S1■I4 dregs, which was determined by using the formula h, -h (α is the extinction coefficient).7 From this figure, As is clear, the optical gap widens as the nitrogen content increases. For example, m of NH3
When the ol concentration is 26%, 2. It becomes Oev. Therefore, it is understood that it is possible to increase the blue sensitivity range for short wavelengths2. Figure 3 shows the photoconductivity (when irradiated with light of A h/11), room temperature conductive dust, and activation energy S+l-L+ The dependence on the molar ratio of N1-13 gas to gas is shown. Photoconductivity and room temperature conductive dust increase with increasing nitrogen content;
'l-f:+ has a maximum value at 26 mo1% and tends to decrease later.

In particular, the photoconductivity is 1.6 x I F" (Ω-Cm)-1 for N1-13 at 26%, which is an improvement of more than two orders of magnitude compared to the non-doped case. .

In addition, the activation energy is 1ηol concentration of Nl'3 is 2
Even when it increased to 6%, no significant change was observed.

Figure 4 shows the dependence of photoconductivity on photon energy. Compared to non-doped amorphous silicon containing 26 mo1% of NHa gas basin, when the photon energy is 22ev or less, it is about two orders of magnitude higher than that of non-doped silicon. It can be seen that an even greater improvement has been made on the high energy side of 2.2 eV or more, where the sensitivity decreases in the case of phoI-no energy.

The first item is a table of the experimental results conducted by the inventors, and shows the nitrogen atom content kEr of nitrogen-containing hydrogenated amorphous silicon determined by oxidation/engineering analysis. , For further reference, the concentration of N'l-13 is 230
Plasma CV1 when m01%. ) I was very impressed with the quality of SiN.

From the experimental results described above, the photoconductivity was determined by 1n, and also yc: Gakujitsubu qJ)r, and the area Kim could be combined with N[13 gas Si t- Nitrogen-containing hydrogenated amorphous /lico/precipitated from Umikano 12-kuber with 11[)0.1φ of 6-60 for 14Jj, that is, containing 6-37 nitrogen atoms in composition ratio. It can be seen that hydrogenated amorphous silicon is a good choice for determining the ability to form a sensitive layer.

In addition, the inventors of the present invention believe that microcrystalline silicon and amorphous silicon are uniformly distributed, and that microcrystalline silicon and amorphous silicon have a structure in which the crystal structure changes continuously from 1 to 1. It was discovered through extensive human experimentation as described below that the red sensitivity of amorphous silicon is higher than that of amorphous silicon.

The sample used in the experiment was prepared as follows.

A vertical fc of O~O,B+<a was applied to a quartz or silicon substrate placed in a claw discharge reaction chamber, and a total H2 gas content of 1 or 10 m01% was applied.
t-14 Kasuke style @, introduced in 27 SCCM-Z11
TS, Frequency 13.56 NYI-Iz, Power 5-50
A claw discharge was performed under W discharge conditions to uniformly distribute microcrystalline silicon to amorphous silicon, and furthermore, the crystal structure was continuously changed. The pressure inside the reaction chamber at the time of sample preparation was approximately 0.02'l'', or r rT. substrate,
゛Illuminance is 250℃~300℃, typically (300℃
I used a tray.

Next, the optical and electrical properties of the microcrystalline silicon obtained as described above will be shown.

Figure 5 shows the results of Xi diffraction of the prepared microcrystal "Hinlicon". This figure shows that microcrystals did not appear in the case of amorphous silicon (111
) It can be seen that a diffraction peak corresponding to the lattice plane appears near the 20-28' range, and that the height of the peak increases as the microcrystalization continues to increase. The half-width 1 of the Natako peak continues to take a constant value of about 15'' even if the peak height changes, so it depends on the grain size of about 5''.
It was found that OA) remained unchanged and the number of crystal grains increased 4), and that for each microcrystalline silicon, the In addition, it was found that microcrystallization was performed when the room temperature conductivity σRT was .-10""(member.C711)' or more.

Figures 6 and 7 are 1(・1・゛Power 50W and 25W, respectively)
This figure shows the dependence of the extinction coefficient on the optical energy of microcrystalline FH/licon when prepared from W. As is clear from these figures, it can be seen that hydrogenated amorphous silicon has significantly degraded absorption of 1 red element compared to crystal warp=17. This means that the optical gap of amorphous silicon is about i,7ev and that of single crystal silicon is about 11QV.
3, Figures 6 and 7 show four examples of microcrystallized 711 cones with different manufacturing conditions (H, P. )1% is 50'W, 1%150W, 10%/
25W, 1%/25W110%) is shown3,
In all of these four examples, the extinction coefficient at long wavelength V is close to that of single crystal, but at short wavelengths of 20e or more, the properties of an amorphous solicon remain and are higher than that of single crystal silicon. It has an extinction coefficient. It can be seen that the higher the I (I) power is, the more microcrystallization progresses.

FIG. 8 shows the dependence of photoconductivity (photon number ~ 10 sl, photon energy 2e), optical gap, and activation energy on room temperature conductivity. The photoconductivity tends to increase with microcrystalization. The optical gap decreases with microcrystalization, and the room temperature conductivity decreases to lo-4.
(Ω・(7))=ft%- is about 1. , 5 ev
We also found that the extinction coefficient at a photon energy of l, 5 eV is ~l Q” cyn
-'.

Therefore, it is understood that microcrystalline silicon has a higher tW sensitivity to red than amorphous silicon. However, it was found that the activation energy decreases with microcrystallization.

As explained above, the original conductive photoreceptor is formed by providing a photosensitive layer on a substrate with hydrogenated amorphous silicon containing nitrogen as an all-blue light-sensitive light-receiving region and microcrystalline silicon as a red-sensing light-receiving region. It can have photosensitive properties over a wide wavelength range VC, which can completely cover the whole range and also cover a considerable range of wavelength ranges of sunlight.

FIG. 9 shows a preferred embodiment of the present invention when the conductive photoreceptor is used as the original detection section of the imaging probe.

p+'! by diffusion into the n-type semiconductor substrate 10! 11k11 is provided. Above this p region 11, a p-type microcrystalline 7977 layer 13 nitrogen-containing amorphous silicon layer 14 and an n-type nitrogen-containing amorphous silicon layer 12 are provided as electron blocking layers. Amorphous silicon 7 layers 15
A p-1-n type photodiode is constructed by sequentially stacking layers as a hole blocking layer, and a photodetection sound tl is generated. A transparent electrode 16 is provided above the original detection section, and a positive voltage is applied to the transparent electrode 16 from the four power sources 17vc.

Here, the film thickness of the p-type crystallized silicone layer 12 is 0.02~
02μ, I-type machine crystallized noricon layer 13 thickness: 300A
~3μ, preferably 5000A~3μ, the film thickness of the East type nitrogen-containing amorphous silicon layer 14 is 50A~l, preferably 300A~5000ASn type nitrogen @000A
It is desirable that it is 2 to 02μ.

In addition, the original detection part fluorescent p-11 type) first diode type and (
In this case, the type 1 layer in the above embodiment will be IP type or n type.

However, microcrystalline silicon and amorphous/licon are 5ir-
It is well known that pn control can be achieved by mixing p113 (for n-type) and 1321 (6 for p-type) into a chemical vapor consisting of L+, )Iz, etc. In the case of nitrogen-containing Noricon It has been confirmed that pn control is also possible in the same way.

In addition, the microcrystalline silicon layer J3 and the nitrogen-containing silicon layer 1
The boundary of 4 does not need to be clear and may change gradually.

Furthermore, a layer of amorphous silicon that does not contain nitrogen may be provided between the microcrystalline 7937 layer 13 and the nitrogen-containing silicon layer 14.

In this embodiment, an I-type semiconductor substrate was used, but even if a P-type semiconductor substrate is used, an equivalent image pickup element can be obtained by converting all the conductive type cans such as the original detection section.

The incident light 18f enters the original detection unit of the present invention configured in this way.
When irradiated with fi, the blue light is absorbed by the type 1 nitrogen-containing amorphous silicon layer 14 and the red light is absorbed by the star-shaped microcrystalline silicon layer 13, and all electron-hole pairs are generated, and the electrodes 16 and p
When reaching the region 11, the potential of the p+ region 11 increases to 0. This potential increase is proportional to the amount of incident light and is accumulated during the field period. In this way, the holes accumulated in the region 11 are CC,1-).

B 131) Dedicated charge transfer type scanning circuit or X-
)' is read by a multi-IJ type scanning circuit. In the image pickup device of this embodiment, good color and contrast imaging is performed.In this embodiment, the ohmic contact between the semiconductor substrate and the microcrystalline silicon (7) has the advantage of being easy.

FIG. 10 shows a preferred embodiment in which the photoconductor of the invention is used in a photoelectric conversion cell of a solar cell.

The -L layer of the stainless steel substrate 21 is composed of a p-type crystallized silicon layer 22 and an electronic II layer, and on top of this is a l layer.
Type microcrystalline 7917 layer 23.1 Type exocrystalline/recon layer 24
, an l-type nitrogen-containing amorphous/licon layer 25, and an amorphous/licon layer 26 containing l]-type nitrogen are laminated in order as a hole blocking layer 1.
Re p-i-n 2! Il, l(1”+ 7.t h
The f-iontocar@jrX constitutes a photoelectric conversion cell.

Here, 1) Mold machine crystallization/film thickness of recon layer 22 is 300~
500 people, type 1 crystallized/recon layer 23, dish-shaped amorphous 7
177 layer 24. Thickness of 1-type nitrogen-containing amorphous phosphor layer 25 + d total 05~1+, n-type nitrogen-containing J1 crystalline/
Preferably, the thickness of the recon layer 26 is 300 to 5000 Å. An It, J-transparent electrode 27 is provided on the top of this photoelectric conversion cell. Other examples of the photoelectric conversion cell include the same type of cedar as the one made by the original inspection section of the imaging device mentioned in AiJ), and the one made by Yosotokitaigu is also good.

- When sunlight 29 is incident on the photoelectric conversion cell of the present invention, which is configured as described above, the light beam shorter than the blue source is the I-type nitrogen-containing amorphous/recon layer 25, and the green 'L is the I-type. Amorphous trade/
Recon layer 24, light longer than red light is l-type microcrystal 7937
The electrons are absorbed by the layer 23, generate electron-hole pairs, and reach the electrode 27 and the substrate 2, respectively, to generate electromotive chips.

The solar cell of this embodiment can be used to obtain a photovoltaic device with a short circuit voltage.

FIG. 11 shows a preferred embodiment in which the original conductive photoreceptor of the present invention is used as an electrophotographic photoreceptor 5. A support scrap board of an insulator whose conductor or coated surface has been subjected to conductive treatment 3
Microcrystalline Licon in the upper layer of 1: 32, Amorphous/Licon 3
3. It consists of an electrophotographic body having a photosensitive layer in which nitrogen-containing amorphous/recon 34 is laminated in order.

The photosensitive layer can be made of p-n type or p-1-n type diode type metal, and by doing so, it is possible to obtain both higher resolution and higher definition.

In this embodiment, a clear image with good gradation reproducibility can be obtained even from an original document with four colors.

Hydrogenated amorphous silicon containing nitrogen may be formed once on a small photosensitive layer (~, then subjected to electron beam annealing, laser annealing, etc. to microcrystallize it and provide a red-sensitive light-receiving area9. As explained in detail below, the uninvented yC1 monument city.

The photoreceptor (substrate) has a photosensitive layer that has a blue-sensitive photosensitive area made of hydrogenated amorphous/licon containing nitrogen and a red-sensitive photosensitive area made of microcrystalline silicon, so it has a wide surface area. There is a 1st version that has a 7i impact on the Choryo war, 3.

[Brief explanation of the drawing]

Figure 1 shows the absorption W1 coefficient of hydrogenated amorphous/recon containing nitrogen. N1-13 no l concentration of crystalline/licon optical gap 7
, Figure 3 shows the photoconductivity of hydrogenated amorphous phosphor containing nitrogen, the cell conductivity and the activation energy N1-13m (
, 1L concentration dependence is shown in Dashino, Figure 4 shows the 1st and 1L concentration dependence of photoconductivity in Cla 7, and Figure 5 is Dalano showing the results of X Iff diffraction of microcrystallized phosphoric acid. Figures 6 and 7 are graphs showing the optical energy dependence of microcrystalline silicon, and Figure 8 is the graph showing the room temperature conductivity dependence of photoconductivity, optical gigang, and activation energy of microcrystallized silicon. 9 is a sectional view of one unit of an image sensor having the photoconductive photoreceptor of the present invention as a source detection unit, and FIG. A cross-sectional view of the battery. Figure 11 is a cross-sectional view of the uninvented original conductive photoreceptor when used as an all-electrophotographic photoreceptor. 3.10...N-type semiconductor substrate ll p+ region 12.22... Silicon layers 13, 23...I-type machine crystallized silicon layer 14, 25...1-type nitrogen-containing amorphous silicon layer 15.26 - N-type nitrogen-containing amorphous 7937 layer 16
．． 27...Transparent electrode 17...Denryo 21
... Stainless steel substrate 24 L-type amorphous silicon layer 31 ... Support substrate 32 Microcrystalline silicon 33 Amorphous/recon 34 - Nitrogen-containing amorphous silicon No. 7 Fig. 1 needle - / f - sum Figure 8 Figure 9 Figure 10 Figure 11

Claims (1)

[Claims] It is made of hydrogenated amorphous silicon containing 6 to 3 atomic percent of total nitrogen, and microcrystalline silicon and amorphous silicon are uniformly distributed, and these microcrystalline silicon and amorphous silicon are evenly distributed. Silicon is a conductive photoreceptor comprising a photosensitive layer having a red-sensitive light-receiving portion made of silicon and a gold substrate 11V (having a structure in which silicon has a continuously changing crystal structure).